John Redwood and Martin O'Neill discuss Clare Short's approach on BBC Radio 4's Today programme

A spokesman for Prime Minister Tony Blair said the government had a pro-active policy of promoting trade links.

He said the last Tory government got itself "into an awful mess over the linking of aid and trade".

The spokesman added: "It's important that people see an aid policy not necessarily linked to trade in the way that the last government got into difficulties over."

The intervention came after Ms Short was attacked by the Conservatives and business leaders when she revealed she had refused to lobby for UK companies while on a recent overseas trip.

Ms Short's critics say she is prone to mistakes

Ms Short said she had gone to China to speak up for human rights and not to do deals for British exporters.

She said civil servants had pressed her to put in a good word for several companies seeking contracts in China but she had declined.

The Institute of Directors' policy chief, Ruth Lea, said she was "astounded and extremely disappointed" by Ms Short's remarks.

The Director General of the Institute of Exporters, Ian Campbell, condemned Ms Short's approach as simplistic.

He said UK companies frequently made large contributions to overseas aid.

"Where we are giving substantial sums of money, as we are to certain developing countries, if that money is spent buying German or Japanese or French goods, something is a bit adrift," he said.

Mr Blair promoted UK firms on his China trip

"The purpose of aid is to alleviate poverty, help people get better health, water and education.

"But if we are putting our aid into those countries, we would naturally in the business community expect to see some flow of business back from those donations."

Shadow Trade Secretary John Redwood urged Mr Blair to discipline Ms Short for letting British business down.

"Contracts and jobs that could have come to Britain may now go elsewhere because of the International Development Secretary's insouciant attitude," he said.

Liberal Democrat support

But the Liberal Democrats' international development spokeswoman Jenny Tonge agreed with Ms Short's stance.

She said: "The Conservative government was renowned for making aid for developing countries dependent on contracts for private businesses.

"But of course where aid is not involved, ministers and MPs of all parties should be ambassadors for British business abroad."

Ms Short is regarded by many commentators as a free thinker on the left wing of the Labour Party.

She has often been at odds with the Labour leadership. However, she did survive the cabinet reshuffle earlier this year despite being widely tipped to lose her job.